Mass finishing of workpieces is widely employed in the processing of the workpieces prior to other manufacturing steps such as electroplating and chemical surface treatment (chromating, anodizing, etc.). The barrel, vibratory, centrifugal, and other like techniques for mass finishing cause a mass of workpieces and the surrounding media to move relative to each other with the media impinging upon the surface of the workpiece, and producing a finishing, polishing, or cutting action, depending upon the nature of the media, the hardness of the workpieces, and the nature of the finishing compounds which may be used in connection therewith. In some instances, only deburring is desired; and other instances, polishing and other controlled degrees of surface furnishing are desired.
Among the various types of media used in such mass finishing operations are natural media such as stone, wood, and ground corn cobs; synthetic media such as ceramic-bonded abrasive particles, resin-bonded abrasive particles, and fused aluminum oxide; and metallic media, such as steel and zinc balls, rods, pins, and other elements of various configurations.
As indicated, there may be used in connection with the media finishing, compositions which tend to keep the workpieces and the media clean, and which may have abrasive characteristics to facilitate the surface treatment of the workpieces.
Natural and synthetic media tends to wear away during the finishing process, and generally lose their effectiveness as they are reduced in size and as their contour varies from the optimum contour originally provided. Moreover, the material eroded or broken from the media may interfere with further polishing operations and require a large flow rate of the finishing composition through the media and workpieces to minimize the interference. Metallic media will, when of proper hardness, wear to a significantly lesser extent than the other media, but generally must be used in conjunction with abrasive finishing compounds in order to achieve the desired abrading or polishing action since the surface of the metallic media does not have the abrasive characteristics necessary.
It has been proposed to utilize sintered metal media having a surface configuration which would abrade the surface of the workpieces, but such sintered metal elements are subject to rapid deterioration under the mass finishing conditions, and produce a slurry in the finishing compound which tends to contaminate the workpieces.
It is an object of the present invention to provide a novel method for generating and novel rugged and desirable metal abrading elements for mass finishing of workpieces.
A further object is to provide a novel method for mass finishing of workpieces using novel metallic abrading elements configured to provide abrading surfaces.